United posted a 2-0 win at Aston Villa to clinch a place in the Barclays Under-21 Premier League elite phase.
Warren Joyce's side needed to win the final group game to qualify - either via the top two or the best third-placed side depending on how Villa fare in their final fixture - with Bebe and Federico Macheda conjuring up the goals in the second half.
It was no more than the Reds deserved for a fine performance after the break and Macheda's late second ensured there was no route back for the Midlanders.
Villa were the brighter side in a low-key start with Danny Johnson firing wide and Graham Burke returning Jonny Sutherland's loose kick-out with interest but the ball deflected behind the goal.
Mason Watkins-Clark was relieved to only receive a yellow card after a wild tackle on Davide Petrucci as things were rather scrappy in a tussle mainly played out in midfield. Villa's first-team boss Paul Lambert moved to the bench to offer advice to Gordon Cowans and Sutherland had to scamper to keep out a Burke shot from a difficult angle.
United struggled to test Calum Barrett as Petrucci mishit a shot wide after some delightful skill before Ryan Tunnicliffe's inspiring run could not find a finish from Macheda in the middle due to Bradley Lewis' last-ditch tackle.
A Macheda cross looped off Watkins-Clark and over his own bar and the same player was later grateful to Barrett for keeping out another deflection. Tom Thorpe and Michael Drennan traded off-target efforts but it was no real surprise that the first half ended goalless.